feat: add pkce support to oidc server (#766)

* feat: add pkce support to oidc server

* tests: add test cases for pkce

* fix: review comments

* chore: remove debug line

* chore: remove simple logger from testing

* tests: add test for invalid challenge method

* chore: fix typo

internal/repository/models.go

@@ -5,13 +5,14 @@
 package repository
 
 type OidcCode struct {
-	Sub         string
-	CodeHash    string
-	Scope       string
-	RedirectURI string
-	ClientID    string
-	ExpiresAt   int64
-	Nonce       string
+	Sub           string
+	CodeHash      string
+	Scope         string
+	RedirectURI   string
+	ClientID      string
+	ExpiresAt     int64
+	Nonce         string
+	CodeChallenge string
 }
 
 type OidcToken struct {